Copper or silver complexes with fluorinated diketones and unsaturated ligands

ABSTRACT

A composition of matter of the formula ##STR1## where M is Cu(I) or Ag(I); R 1  is C 1  -C 6  fluoroalkyl, C 1  -C 8  alkyl, C 4  -C 6  heterocycle containing O, S or N or C 6  -C 10  aryl; R 2  is H or C 1  -C 6  alkyl, with the proviso that R 1  and R 2  together with the carbons to which they are attached may be joined together to form a C 6  ring; L is an unsaturated hydrocarbon containing at least one non-aromatic unsaturation; x and y are 1 or 2; and n is from 1 to 8.

BACKGROUND OF THE INVENTION

This invention relates to new copper or silver complexes containing a fluorinated diketonate and unsaturated hydrocarbons as ligands. More particularly, copper or silver in the +1 formal oxidation state form complexes with fluorinated beta-diketonates and unsaturated ligands containing at least one nonaromatic unsaturation.

It is known that certain silver(I) and copper(I) salts form complexes with olefins and acetylenes. For example, cuprous chloride is known to form complexes with both ethylene and acetylene. U.S. Pat. No. 3,401,112 teaches a method of separating a mixture of hydrocarbons having differing degrees of unsaturation using a copper(I) salt of the formula CuXA where XA is an anion, X is oxygen or fluorine and A is the remainder of the anion. Examples of fluorinated anions include fluoro substituted carboxylates, fluorosulphonate, perfluoroborate, hexafluorophosphate and hexafluoroantimonate. CuXA forms a cuprous complex with said unsaturated hydrocarbon. Similarly, U.S. Pat. No. 3,517,079 describes a process for separating vinyl aromatic hydrocarbons from alkyl aromatic hydrocarbons using a cuprous fluoroborate or cuprous fluorophosphate salt wherein a complex is formed. U.S. Pat. Nos. 3,754,047 and 3,755,487 relate to a process for separating complexible ligands such as olefins, acetylenes, aromatics, CO and the like from feedstreams by contacting the feedstream with a cuprous salt including CuBF₄, CuPF₆ and CuOOCCF₃.

SUMMARY OF THE INVENTION

It has been discovered that copper(I) and silver(I) can form a new class of complexes with fluorinated acetylacetonate anions and unsaturated hydrocarbons as ligands. The complexes of the invention have the formula ##STR2## where M is Cu(I) or Ag(I); R¹ is C₁ -C₆ fluoroalkyl, C₁ -C₈ alkyl, C₄ -C₆ heterocycle containing O, S or N or C₆ -C₁₀ aryl; R² is H or C₁ -C₆ alkyl with the proviso that R¹ and R² together with the carbons to which they are attached may be joined together to form a C₆ ring; L is an unsaturated hydrocarbon ligand containing at least one non-aromatic unsaturation capable of forming a Cu-L bond, preferably an unsaturated hydrocarbon containing at least one ethylenic, acetylenic or isonitrilic unsaturation; x and y are 1 or 2; and n is an integer from 1 to 8.

DETAILED DESCRIPTION OF THE INVENTION

The present Cu(I) complexes contain fluorinated acetylacetonate anions and unsaturated hydrocarbons as ligands. Preferred fluorinated acetylacetonate anion ligands have the formula ##STR3## where R¹ is C₁ -C₃ fluoroalkyl, especially CF₃, C₁ -C₆ alkyl, C₆ -C₁₀ aryl or C₄ -C₅ heterocycle containing O, S or N, R² is H with the proviso that R¹ and R² may join together to form a C₆ ring, and n is an integer from 1 to 4, especially 1. Examples of neutral preferred embodiments of fluorinated acetylacenates incorporated into the present complexes as anions include ##STR4##

Preferred unsaturated hydrocarbons are (a) alkenes of the formula ##STR5## where each R³ -R⁶ is independently H; C₁ -C₃₀, more preferably C₁ -C₁₅ and especially C₁ -C₈ aliphatic with the proviso that any combination of R³, R⁴, R⁵ and R⁶ may be joined together to form at least one C₄ -C₁₄, more preferably C₅ -C₁₂, most preferably C₆ -C₈ cycloaliphatic ring; --C.tbd.N; C₆ -C₁₀ aryl; C₇ -C₁₄ araliphatic; ##STR6## where m and p are 0 or 1, R⁷ is C₁ -C₂₀, preferably C₁ -C₁₀ aliphatic, and R⁸ is H, C₁ -C₁₀ aliphatic or C₆ -C₁₀ aryl with the proviso that adjacent ##STR7## may be joined together to form a C₄ -C₁₆ anhydride; (b) alkynes of the formula R⁹ --C.tbd.C--R¹⁰ where R⁹ and R¹⁰ are independently H; C₁ -C₃₀, more preferably C₁ -C₁₅ and especially C₁ -C₈ aliphatic; C₆ -C₁₀ aryl or C₇ -C₁₄ araliphatic; or (c) isonitriles of the formula R¹¹ --N.tbd.C where R¹¹ is C₁ -C₂₀ aliphatic; C₃ -C₁₀ cycloaliphatic; C₇ -C₂₀ araliphatic or C₆ -C₁₀ aryl. The unsaturated hydrocarbons may be substituted with unreactive substituents such as halogen, cyano, alkoxy, nitro, and the like.

Examples of suitable unsaturated ligands include: ethylene, acetylene, 1-octene, isobutylene, 1,5-cyclooctadiene, stilbene, diphenylacetylene, styrene, cyclooctene, 1,5,9-cyclododecatriene, 1,3-hexadiene, isopropylacetylene, 1-decene, 2,5-bicycloheptadiene, 1-octadecene, cyclopentene, octalin, methylene cyclohexane, diphenyl fulvene, 1-octadecyne, benzyl cinnamate, benzal acetophenone, acrolein, acrylonitrile, maleic anhydride, oleic acid, linolenic acid, acrylic acid, methyl methacrylate and diethyl maleate. Suitable isonitriles are, e.g., methyl isocyanide, butyl isocyanide, cyclohexyl isocyanide, phenylethyl isocyanide and phenyl isocyanide.

Examples of copper(I) and silver(I) complexes are as follows. ##STR8##

The complexes of the invention may be prepared by reacting metal oxide, fluorinated acetylacetone and unsaturated ligand in an inert organic solvent. The preparation of a cuprous complex is illustrated by the following equation: ##EQU1## Silver(I) complexes are similarly prepared. Reactants are preferably combined in approximately stoichiometric amounts. The amounts, however, are not critical and variations therefrom are possible. The reaction preferably takes place in an inert organic solvent. Preferred solvents are ethers, ketones, esters, alcohols, saturated aliphatic hydrocarbons, aromatic hydrocarbons and the like. It is necessary that the amount of CO in the reaction mixture not exceed about 10 vol%. In the above preparative reaction, CO competes with unsaturated ligand in the formation of cuprous complex and based on thermodynamic considerations, a CO complex forms in preference to the unsaturated ligand complex as long as competing amounts of CO are present. It is also desirable to carry the preparative reaction in an inert atmosphere, since gases such as oxygen may result in the oxidation of Cu(I) to Cu(II). Complexes according to the invention may also be prepared by the following reaction schemes: ##EQU2##

Reaction times are not critical. Generally, the reaction mixture is stirred until a clear solution is obtained. A solid product may then be isolated by evaporating solvent. Suitable temperatures are from about -100° to +100° C. with room temperature being preferred. If the reaction mixture is heated excessively, it is possible that a dissociative reaction may take place, leading to a decrease in yield. Thus, copper(I) ethylene complexes are rather unstable due to a high dissociative pressure and heating would not be desirable. On the other hand, higher molecular weight olefins result in stable compounds, and the reaction mixture can be heated without harmful results with respect to yields.

Copper(I) and silver(I) complexes according to the invention are useful in gas separation processes and as catalysts or catalyst precursors. The complexes are further illustrated in the following examples.

EXAMPLE 1

A suspension of 1.45 g (0.01 mole) cuprous oxide in 75 ml methylene chloride was stirred with 2.16 g (0.02 mole) of 1,5-cyclooctadiene in a 250 ml flask under nitrogen. A solution of 4.16 g (0.02 mole) 1,1,1,5,5,5-hexafluoroacetylacetone (hfacac) in 50 ml methylene chloride was added dropwise over a 30 minute period. Red Cu₂ O gradually dissolved forming a clear yellow solution. The solution was filtered to remove any remaining solids and the solvent was then removed on a rotary evaporator. Cu(1,5-COD) (hfacac) was obtained as bright yellow crystals which could be purified by recrystallization from hexane. The product was characterized by IR and MNR spectroscopy and elemental analysis.

EXAMPLE 2

This example illustrates the preparation of complexes using CuI, a thallium salt and unsaturated ligand. To 50 ml of CH₂ Cl₂ was added 0.93 g CuI and 0.53 g of 1,5-cyclooctadiene (COD). After stirring for 20 minutes, 2.0 g of thallium hexafluoroacetylacetonate was added and the mixture stirred overnight. TlI was separated by filtration and the filtrate evaporated to give 1.85 g of crystalline Cu(COD) hfacac.

EXAMPLES 3-42

Using the techniques described in Example 1, other complexes were prepared as shown in the following table.

                                      TABLE I                                      __________________________________________________________________________     Ex.                      Metal Oxide                                           No.                                                                               Ligand (mmol)                                                                            β-diketone, (mmol)                                                                    (mmol) Solvent                                                                              Compound Formed                          __________________________________________________________________________     3  1,5-cyclooctadiene                                                                       thenoyltrifluoro-                                                                          Cu.sub.2 O (9.0)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu (COD) TTA                                (COD) (9.0)                                                                              acetylacetone (TTA) (14.0)                                        4  1,5-cyclooctadiene                                                                       hexafluoroacetyl-                                                                          Cu.sub.2 O (11.0)                                                                     C.sub.6 H.sub.5 CH.sub.3                                                             Cu (COD) hfacac                             (20.0)    acetone (hfacac)                                                               (18.0)                                                            5  1,3-butadiene                                                                            hexafluoroacetyl-                                                                          Cu.sub.2 O (7.0)                                                                      THF   Cu(C.sub.4 H.sub.6) hfacac*                 (large excess)                                                                           acetone (14.0)                                                    6  Diphenylacetylene                                                                        hexafluoroacetyl-                                                                          Cu.sub.2 O (3.0)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu(φCCφ).sub.2 hfacac               (9.65)    acetone (4.81)                                                    7  Diphenylacetylene                                                                        trifluoroacetyl-                                                                           Cu.sub.2 O (3.0)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu(φCCφ).sub.2 tfacac               (9.65)    acetone (tfacac)                                                               (4.80)                                                            8  1,5-cyclooctadiene                                                                       trifluoroacetyl-                                                                           Cu.sub.2 O (11.0)                                                                     CH.sub.2 Cl.sub.2                                                                    Cu(COD) tfacac                              (20.0)    acetone (18.0)                                                    9  Bicyclo[2.2.1] hepta-2,5-diene (22.0)                                                    hexafluoroacetyl- acetone (21.0)                                                           Cu.sub.2 O (11.0)                                                                     CH.sub.2 Cl.sub.2                                                                     ##STR9##                                10 cyclohexyliso- nitrile (13.0)                                                            hexafluoroacetyl- acetone (6.0)                                                            Cu.sub.2 O (3.0)                                                                      CH.sub.2 Cl.sub.2                                                                     ##STR10##                               11 Bicyclo[2.2.1]-2- heptene (18.0)                                                         hexafluoroacetyl- acetone (17.0)                                                           Cu.sub.2 O (11.0)                                                                     CH.sub.2 Cl.sub.2                                                                     ##STR11##                               12 1,3,5,7-cyclo-                                                                           trifluoroacetyl-                                                                           Cu.sub.2 O (4.0)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu(COT) tfacac                              octatetraene (7.5)                                                                       acetone (7.1)                                                     13 1,3,5,7-cyclo-                                                                           trifluoroacetyl-                                                                           Cu.sub.2 O (4.0)                                                                      CH.sub.2 Cl.sub.2                                                                    [Cu(tfacac)].sub.2 COT                      octatetraene (3.6)                                                                       acetone (7.2)                                                     14 2-hexyne (5.0)                                                                           hexafluoroacetyl-                                                                          Cu.sub.2 O (2.5)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu(CH.sub.3 CCC.sub.3 H.sub.7)                        acetone (4.3)            hfacac                                   15 styrene (11.5)                                                                           hexafluoroacetyl-                                                                          Cu.sub.2 O (5.00)                                                                     CH.sub.2 Cl.sub.2                                                                    Cu(CH.sub.2CHφ)                                   acetone (9.61)           hfacac                                   16 isoprene (15.0)                                                                          hexafluoroacetyl- acetone (7.3)                                                            Cu.sub.2 O (4.0)                                                                      CH.sub.2 Cl.sub.2                                                                     ##STR12##                               17 ethylene (large                                                                          hexafluoroacetyl-                                                                          Cu.sub.2 O (3.5)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu(CH.sub.2CH.sub.2)hfacac*                 excess)   acetone (6.9)                                                     18 2,8-decadiyne                                                                            hexafluoroacetyl-                                                                          Cu.sub.2 O (8.0)                                                                      CH.sub.2 Cl.sub.2                                                                    [Cu(hfacac)].sub.2 CH.sub.3 CC              (15.0)    acetone (14.0)           (CH.sub.2).sub.4 CCCH.sub.3              19 1,5-cycloocta-                                                                           3-trifluoroacetyl-                                                                         Cu.sub.2 O (2.0)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu(COD) (TAC)                               diene (4.5)                                                                              d-camphor (TAC) (4.0)                                             20 cyclohexene (27.0)                                                                       hexafluoroacetyl- acetone (12.0)                                                           Cu.sub.2 O (7.0)                                                                      CH.sub.2 Cl.sub.2                                                                     ##STR13##                               21 Bicyclo[2.2.1]- 2-heptene (14.0)                                                         trifluoroacetyl- acetone (13.0)                                                            Cu.sub.2 O (6.5)                                                                      CH.sub.2 Cl.sub.2                                                                     ##STR14##                               22 cyclohexyliso- nitrile (16.0)                                                            trifluoroacetyl- acetone (8.2)                                                             Cu.sub.2 O (15.0)                                                                     CH.sub.2 Cl.sub.2                                                                     ##STR15##                               23 phenylacetylene                                                                          hexafluoroacetyl-                                                                          Cu.sub.2 O (8.0)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu(φCCH) hfacac                         (15.0)    acetone (15.0)                                                    24 cyclooctene (COE)                                                                        hexafluoroacetyl-                                                                          Cu.sub.2 O (4.6)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu(COE) hfacac                              (9.07)    acetone (9.0)                                                     25 propene (large                                                                           hexafluoroacetyl-                                                                          Cu.sub.2 O (3.5)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu(CH.sub.3 CHCH.sub.2)                     excess)   acetone (6.9)            hfacac*                                  26 1-decene (24.0)                                                                          hexafluoroacetyl-                                                                          Cu.sub.2 O (14.0)                                                                     CH.sub.2 Cl.sub.2                                                                    Cu(CH.sub.2CHC.sub.8 H.sub.17)                        acetone (24.0)           hfacac                                   27 3-methylcyclo- hexene (15)                                                               hexafluoroacetyl- acetone (9.0)                                                            Cu.sub.2 O (5.0)                                                                      CH.sub.2 Cl.sub.2                                                                     ##STR16##                               28 1,3,5,7-cyclo-                                                                           hexafluoroacetyl-                                                                          Cu.sub.2 O (4.0)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu(COT) hfacac                              octatetraene (7.5)                                                                       acetone (7.2)                                                     29 1,3,5,7-cyclo-                                                                           hexafluoroacetyl-                                                                          Cu.sub.2 O (4.0)                                                                      CH.sub.2 Cl.sub.2                                                                    [Cu(hfacac)].sub.2 COT                      octatetraene (3.6)                                                                       acetone (7.2)                                                     30 (+)-α-pinene                                                                       hexafluoroacetyl-                                                                          Cu.sub.2 O (4.0)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu(α-pinene)                          (7.5)     acetone (7.4)            hfacac                                   31 3-methyl-cyclo- hexene (8.0)                                                              3-trifluoroacetyl- d-camphor (6.0)                                                        Cu.sub.2 O (3.5)                                                                      CH.sub.2 Cl.sub.2                                                                     ##STR17##                               32 d,1-α-pinene                                                                       3-trifluoroacetyl-d-                                                                       Cu.sub.2 O (3.5)                                                                      CH.sub.2 Cl.sub.2                                                                    Cu(d-α-pinene) TAC                    (8.0)     camphor (6.0)            +Cu (1-α-pinene) TAC,                                                    mixed diastereomers                      33 1,5-cycloocta-                                                                           hexafluoroacetyl-                                                                          Ag.sub.2 O (0.56)                                                                     CH.sub.2 Cl.sub.2                                                                    Ag(COD) hfacac                              diene (1.12)                                                                             acetone (1.12)                                                    34 ethylene (large                                                                          hexafluoroacetyl-                                                                          Ag.sub.2 O (2.16)                                                                     CH.sub.2 Cl.sub.2                                                                    Ag(CH.sub.2CH.sub.2) hfacac*                excess)   acetone (4.28)                                                    35 diphenylacetyl-                                                                          hexafluoroacetyl-                                                                          Ag.sub.2 O (2.16)                                                                     CH.sub.2 Cl.sub.2                                                                    Ag(φCCφ ).sub.2 hfacac              ene (8.64)                                                                               acetone (4.30)                                                    36 cyclooctene (8.64)                                                                       hexafluoroacetyl-                                                                          Ag.sub.2 O (4.37)                                                                     CH.sub.2 Cl.sub.2                                                                    Ag(COE) hfacac                                        acetone (8.64)                                                    37 propylene (large                                                                         hexafluoroacetyl-                                                                          Ag.sub.2 O (2.16)                                                                     CH.sub.2 Cl.sub.2                                                                    Ag(CH.sub.3 CHCH.sub.2)hfacac               excess)   acetone (4.28)                                                    38 1-decene (4.4)                                                                           hexafluoroacetyl-                                                                          Ag.sub.2 O (2.2)                                                                      CH.sub.2 Cl.sub.2                                                                    Ag(CH.sub.2CHC.sub.8 H.sub.17)                        acetone (4.3)            hfacac                                   39 1,3-butadiene                                                                            hexafluoroacetyl-                                                                          Ag.sub.2 O (2.16)                                                                     CH.sub.2 Cl.sub.2                                                                    Ag(CH.sub.2CHCHCH.sub.2)                    (large excess)                                                                           acetone (4.3)            hfacac*                                  40 bicyclo[2.2.1]- 2-heptene (4.4)                                                          hexafluoroacetyl- acetone (4.3)                                                            Ag.sub.2 O (2.2)                                                                      CH.sub.2 Cl.sub.2                                                                     ##STR18##                               41 bicyclo[2.2.1] hepta-2,5-diene (4.4)                                                     hexafluoroacetyl- acetone (4.3)                                                            Ag.sub.2 O (2.2)                                                                      CH.sub.2 Cl.sub.2                                                                     ##STR19##                               42 diethylmaleate (100)                                                                     hexafluoroacetyl- acetone (20.0)                                                           Cu.sub.2 O (10.0)                                                                     none                                                                                  ##STR20##                                                                     OC.sub.2 H.sub.5)hfacac                  __________________________________________________________________________      *Not stable at room temperature.                                          

What is claimed is:
 1. A composition of matter comprising a complex of the formula ##STR21## where M is Cu(I); R¹ is C₁ -C₆ fluoroalkyl, C₁ -C₈ alkyl, C₄ -C₆ heterocycle containing O, S or N or C₆ -C₁₀ aryl; R² is H or C₁ -C₆ alkyl with the proviso that R¹ and R² together with the carbons to which they are attached may be joined together to form a C₆ ring; L is an unsaturated hydrocarbon ligand containing at least one non-aromatic unsaturation; x and y are 1 or 2; and n is from 1 to
 8. 2. The composition of claim 1 wherein L is an unsaturated hydrocarbon containing at least one ethylenic, acetylenic or isonitrilic unsaturation.
 3. The composition of claim 1 wherein L is an (a) alkene of the formula ##STR22## where each R³ -R⁶ is independently H; C₁ -C₃₀ aliphatic with the proviso that any combination of R³, R⁴, R⁵ and R⁶ may be joined together to form at least one C₄ -C₁₄ cycloaliphatic ring; --C.tbd.N; C₆ -C₁₀ aryl; C₇ -C₁₄ araliphatic; ##STR23## where m and p are 0 or 1, R⁷ is C₁ -C₂₀ aliphatic, R⁸ is H, C₁ -C₁₀ aliphatic or C₆ -C₁₀ aryl with the proviso that adjacent ##STR24## may be joined together to form a C₄ -C₁₆ anhydride; (b) alkyne of the formula R⁹ --C.tbd.C--R¹⁰ where R⁹ and R¹⁰ are independently H; C₁ -C₃₀ aliphatic; C₆ -C₁₀ aryl or C₇ -C₁₄ araliphatic; or (c) isonitrile of the formula R¹¹ --N.tbd.C where R¹¹ is C₁ -C₂₀ aliphatic; C₃ -C₁₀ cycloaliphatic; C₇ -C₂₀ araliphatic or C₆ -C₁₀ aryl.
 4. The composition of claim 3 wherein L is substituted with halogen, cyano, alkoxy or nitro.
 5. The composition of claim 1 wherein R¹ is C₁ -C₃ fluoroalkyl, C₁ -C₆ alkyl, C₆ -C₁₀ aryl or C₄ or C₅ heterocycle containing O, S or N.
 6. The composition of claim 1 wherein R¹ is CF₃ and n is
 1. 7. The composition of claim 1 wherein n is
 1. 8. The composition of claim 1 wherein R² is H.
 9. The composition of claim 3 wherein R³ -R⁶ are independently H, C₁ -C₁₅ aliphatic, C₅ -C₁₂ cycloaliphatic, C₆ -C₁₀ aryl or C₇ -C₁₄ araliphatic.
 10. The composition of claim 3 wherein m is 0 and p is
 1. 11. The composition of claim 3 wherein R¹ is CF₃, CH₃ or ##STR25##
 12. The composition of claim 3 wherein R¹ is CF₃, R² is H, n is 1, x and y are 1 and L is ##STR26##
 13. A composition of matter comprising a complex of the formula ##STR27## where M is Cu(I); R¹ is C₁ -C₆ fluoroalkyl, C₁ -C₈ alkyl, C₄ -C₆ heterocycle containing O, S or N or C₆ -C₁₀ aryl; R² is H or C₁ -C₆ alkyl with the proviso that R¹ and R² together with the carbons to which they are attached may be joined together to form a C₆ ring; L is an alkene, alkyne or isonitrile; x and y are 1 or 2; and n is from 1 to
 8. 14. A composition of matter comprising a complex of the formula ##STR28## where M is Ag(I); R¹ is C₁ -C₆ fluoroalkyl, C₁ -C₈ alkyl, C₄ -C₆ heterocycle containing O, S or N or C₆ -C₁₀ aryl; R² is H or C₁ -C₆ alkyl with the proviso that R¹ and R² together with the carbons to which they are attached may be joined together to form a C₆ ring; L is an (a) alkene of the formula ##STR29## where each R³ -R⁶ independently H; C₁ -C₃₀ aliphatic; --C.tbd.N; C₆ -C₁₀ aryl; C₇ -C₁₄ araliphatic; ##STR30## where m and p are 0 or 1, R⁷ is C₁ -C₂₀ aliphatic, R⁸ is H, C₁ -C₁₀ aliphatic or C₆ -C₁₀ aryl with the proviso that adjacent ##STR31## may be joined together to form a C₄ -C₁₆ anhydride; (b) alkyne of the formula R--⁹ C.tbd.C--R¹⁰ where R⁹ and R¹⁰ are independently H; C₁ -C₃₀ aliphatic; C₆ -C₁₀ aryl or C₇ -C₁₄ araliphatc; or (c) isonitrile of the formula R¹¹ --N.tbd.C where R¹¹ is C₁ -C₂₀ aliphatic; C₃ -C₁₀ cycloaliphatic; C₇ -C₂₀ araliphatic or C₆ -C₁₀ aryl.
 15. A method for preparing the composition of claim 1 which comprises contacting M₂ O where M is Cu with ##STR32## and L in an inert organic solvent and in an inert atmosphere at temperatures of from -100° to +100° C. 